Does a wire in a closed circuit induce a voltage on itself?

In summary, Faraday's Law states that a changing magnetic field can induce an electric field, which can then create a current in a nearby wire. This can occur when current is running through a wire in a closed circuit and the magnetic field changes in time. The induced current may oppose or add to the original current, depending on the circumstances and the principles of inductance and Lenz's law. In the real world, the magnetic field is constantly changing due to fluctuations in current, and this can also occur in a perfect circuit when it is initially open and then closed. In an AC circuit, the current and magnetic field will constantly be oscillating, leading to a continuous induction of current. This effect is described by the terms "ind
  • #1
rail2k
5
0
According to Faraday's Law a changing magnetic field induces an electric field, an example of this is if you have a wire close enough to another wire with current flowing through it the first wire will also have current run through it because of the induced electric field by the second wire.

As current runs through a wire in a closed circuit a magnetic field is created around the wire, so doesn't that mean that that same magnetic field will induce an electric field which will create more current in the wire? If it does, then is the new current opposing the original current or adding to it?
 
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  • #2
Only when the magnetic field is changing in time (increasing or decreasing).
It may oppose or add. See "inductance" and "Lenz's law".
 
  • #3
But in the real world when current runs through a closed circuit doesn't the magnetic field constantly change due to a never steady current, just by extremely small amounts?

And in a perfect circuit, if the circuit is initially open but then you close it won't the magnetic field increase as current first travels through the circuit (extremely fast of course)?

If either of those are right, wouldn't the changing magnetic field induce a current to oppose or add to the original current?

EDIT: If you were using an AC power source, wouldn't the current and the magnetic field constantly be oscillating? So then this would constantly induce current, right?
 
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  • #4
In a DC circuit you will have this effect when you turn ON or OFF the power.
In an AC circuit you will have this induced emf whose effect is described by the "inductive reactance". Look up these terms for more information.
 
  • #5


Yes, according to Faraday's Law, a changing magnetic field can induce an electric field, which can then create a current in a nearby wire. This phenomenon is known as electromagnetic induction. In the scenario described, the changing magnetic field created by the first wire's current can induce an electric field in the second wire, causing current to flow through it as well.

The direction of the induced current will depend on the direction of the changing magnetic field. If the magnetic field is increasing, the induced current will flow in the opposite direction of the original current, creating a opposing effect. If the magnetic field is decreasing, the induced current will flow in the same direction as the original current, adding to it.

It is important to note that the strength of the induced current will depend on factors such as the distance between the wires, the strength of the magnetic field, and the properties of the wires themselves. Additionally, the induced current will only occur while there is a changing magnetic field present.

In conclusion, a wire in a closed circuit can indeed induce a voltage on itself through electromagnetic induction. The direction and strength of the induced current will depend on the factors mentioned above. This phenomenon is important to consider in circuits and can be utilized in various technologies such as transformers and generators.
 

1. How does a wire in a closed circuit induce a voltage on itself?

A wire in a closed circuit can induce a voltage on itself through the phenomenon of self-induction. When a current flows through a wire, it creates a magnetic field around the wire. This changing magnetic field can then induce a voltage in the wire itself, causing a current to flow in the opposite direction. This self-induced voltage can be calculated using Faraday's law of induction.

2. What is self-inductance and how does it relate to a wire in a closed circuit?

Self-inductance is the property of a wire or any other electrical conductor to create an induced voltage in itself when the current flowing through it changes. This is due to the magnetic field produced by the changing current. In a closed circuit, the wire's self-inductance can cause a voltage to be induced on itself, which can affect the behavior of the circuit.

3. Can a wire in a closed circuit induce a voltage on itself even without any external power source?

Yes, a wire in a closed circuit can induce a voltage on itself even without any external power source. This is because the flow of current in the wire itself creates a changing magnetic field, which in turn induces a voltage in the wire. This phenomenon is known as self-induction and is a fundamental concept in electromagnetism.

4. How does the length and thickness of a wire affect the self-induced voltage in a closed circuit?

The length and thickness of a wire can affect the self-induced voltage in a closed circuit. Generally, a longer and thinner wire will have a higher self-inductance, resulting in a higher induced voltage. This is because a longer wire has a larger surface area for the magnetic field to act on, and a thinner wire has a higher resistance, resulting in a slower change in current, which further increases the self-induced voltage.

5. Can self-induction cause any problems in a closed circuit?

Yes, self-induction can cause problems in a closed circuit. The induced voltage in a wire can oppose the flow of current, causing a delay in the circuit's response and potentially leading to voltage spikes or other unwanted effects. This is why in high-frequency circuits, measures such as using twisted wires or adding inductors are taken to minimize the effects of self-induction.

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